2-Naphthoic acid ergosterol ester, an ergosterol derivative, exhibits anti-tumor activity by promoting apoptosis and inhibiting angiogenesis

- Our findings indicate that ergosterol (ER) and its derivatives treatment can decrease the tumor weight and increase TIR in the H22-tumor bearing mice, and 2-Naphthoic acid ergosterol ester (NE) showed the better activity in the studied assay.
- It indicated that intraperitoneal injection of NE increased TFN-γ level and TIR but decreased the serum VEGF level of mice bearing H22 liver cancer.
- The evaluation of ALT, AST, BUN and CRE in serum showed NE were little toxicity to mice.
- The H&E study of tumor further strengthened the anti-tumor activity of NE, and the Tunel assay results showed that NE can promote the apoptosis of tumor cells.
- The mechanistic studies showed that NE could stimulate apoptosis through up expression of BAX, and down expression of Bcl-2 and VEGF.
- As array of studies clearly demonstrate that the molecular mechanisms underlying antitumor efficacy of some chemotherapeutic agents are involved in the induction of apoptosis, which is considered to be the preferred measure to treat tumors [21].
- Therefore, NE, a monoester derivative of ER, with low toxicity and high efficacy of anti-tumor is a good promising development that will be practical in clinical trials, and improve the application of NE.

Phytosterol is a natural component of vegetable oil and includes ergosterol (ER) and β-sitosterol. In this study, three new ergosterol monoester derivatives were obtained from the reflux reaction with ergosterol, organic acids (furoic acid, salicylic acid, and 2-naphthoic acid), EDCI, and DMAP in dichloromethane. The chemical structures were defined by IR and NMR. On the basis of the results, 2-naphthoic acid ergosterol ester (NE) had the highest tumor inhibition rate and was selected to study anti-tumor activity and its mechanism at doses of 0.025 mmol/kg and 0.1 mmol/kg in H22-tumor bearing mice. Compared with ER, NE exhibited more stronger anti-tumor activity in vivo. Furthermore, biochemical parameters of ALT, AST, BUN, and CRE showed that NE had little toxicity to mice. NE significantly improved serum cytokine levels of IFN-γ and decreased VEGF levels. Moreover, H&E staining, TUNEL assay, immunohistochemistry, and western blotting indicated that NE exhibited anti-tumor activity in vivo by promoting apoptosis and inhibiting angiogenesis. In brief, the present study provided a method to improve ER anti-tumor activity and a reference for a new anti-tumor agent.